cu top speed 35mph

[937carrera]

That sounds very similar to the issue I am having with mine. I've spent time making sure the timing is correct and adjusting tappets (the correct setting gives no compression). I have been coming to the conclusion that either the valve stems have stretched, or there is valve seat recession

[ghost123uk]

adjusting tappets (the correct setting gives no compression).

This is common when an engine has been built with solid tappets as opposed to the hydraulic ones (which require to be 1/2 a turn or more in after touching). I don't know the solid tappet clearance, but it will be on here somewhere. Tis important not to run a solid tappet engine with less clearance that specified as it can quickly burn out exhaust valves and damage the valve seats.

[itchyfeet]

Wanna borrow my compression tester next Rik?

[dubslug]

Hi guys thanks for the help. The engine was running okay apart from stalling before it went in. Had power etc. He,said he didn't touch tappets. So I havent touched them either. He said stalling was caused by split hoses on manifolds. He then tried to tune it but found no timing mark so took spark one out to get it top dead centre. I'm gutted missed out using it over weekend as planned

[937carrera]

If that's the case then the only adjustment has been to the timing and the replacement of the split hoses. If the problem was split hoses, then I have to wonder why the garage started messing around with the timing

i would check that the replaced hoses have been installed correctly and then re-time the igntion again. If you-reset it correctly and it isn't running as well as before try moving it a couple of degrees at a time until it does. Not all engines work best on the standard settings, so yours might need to be "a bit wrong".

As I said in my earlier post, I found it much easier to remove the safety guard and alternator duct when setting mine. The rest of the instructions are in the linked thread

Good Luck

[dubslug]

I'm going to assume carb was messed about with as he said because of leak from exhaust it couldn't beset up. I will indeed follow the guide again and again till I get it right. Are there any accepted methods of getting the carb settings about right? Like 3 winds out-of the screws or anything so I know I'm at a good Base point

[dubslug]

Just to check I'm doing this right. Put engine to tdc. When at tdc with is slightly offset on gauge, the dizzy rotar arm is about 4 o'clock pointing at little notch on distributor.run engine till warm so both choke are off, then using timing light turn dizzy till I'm getting 6 atdc. I'm guessing the revs as I don't have way of checking. The vac hoses are connected and the idle control box cables joined bypassing the idle control box

[937carrera]

OK, base settings for carbs are in http://www.ratwell.com/technical/DualCarbs.html

For setting the timing look at the post I made earlier. From reading your reply I think you seem to be on the right lines, recheck Boxy's posts as I found them particularly helpful.

After you have set the timing restart and recheck the timing with idle stabilisation on, it should be flitting about 5 degreees BTDC, + / - 5 degrees, or at least that's what mine did.

You should set the timing first, then the carbs

[dubslug]

Hi guys. Right got engine set up timing wise. Took pulley off found notch on pulley so using that. Got that at tdc and then once engine warmed up with the idle stabilisation joined got it running at 6 poss 8 After top dead centre. When revving it pulls backwards into before top dead centre. It's better but Not right yet. Also I'm hearing mixed views on if should be before or after top dead centre. Help please

[CovKid]

Dizzy vacuum unit not working correctly? Sounds it. That would explain the terrible performance.

[dubslug]

Is it not meant to pull into firing before top dead centre as revs rise? I haven't driven it since playing today. Today I have changed plugs filter dizzy cap, leads and rotar arm done few weeks ago. So all parts should be in top form. I know I need to check and adjust valves once um gappy with timing. At the moment on idle it's running between 6 and 8 After top dead centre. Engine sounds like it's okay , can't give it full revs as neighbours complain. So in short does a cu engine run at 6,8 degrees after top dead centre? If so I'm happy mine does so what should the tappets clearances be? Start at one do inlet outlet together? With engine at tdc, rotate 180 anti clockwise do number 2 rotate 180 anti clockwise again do 3 and again for 4?

[937carrera]

Sounds like you are pretty close with the timing, though I think 5 degrees ATDC is the factory spec.

I was reading a useful page in the Wiki earlier today, with comments by some guy called CovKid https://club8090.co.uk/wiki/Pe ... gnition_02

You have the advance curve for the dizzy on that page, and I can confirm that I saw max advance at 30 degrees BTDC when I tested my van. You will need to find somewhere you can run to max revs to test the advance properly

There is no clearance of hydraulic tappets, if everythings working correctly.

Sounds like it's time to go out for a spin and see how things are

[CovKid]

Advance depends on what dizzy is on there. I speed read back through thread and couldn't find any mention of dizzy type. If its a stock one, definately get vacuum unit checked out or it'll be gutless if its twonked. If its a 009, well....

[dubslug]

Im not sure what's on there. It has advance and retard on the dizzy. It's one that I have always had

[CovKid]

Could be that the diaphram in the vac unit is tired. They need to be very responsive to keep up with throttle demands or it'll bog down. Try pulling the advance hose off and with dizzy cap removed, see if the plate inside moves briskly when you suck on the pipe. It should also stay in position if you stick your tongue over the pipe. If it doesn't play ball, you'll have found the culprit.

The hose also needs to be a secure fit with no chance of leaks. The plate itself may be gunked up with old grease - another possibility.